Different roles of cerium substitution and oxygen reduction in transport inPr2−xCexCuO4thin films

Abstract

Using pulsed-laser ablation with an improved oxygen annealing process and Hall effect measurements, we show that the reduction process needed to induce superconductivity in electron-doped cuprates thin films does not trigger a significant change in carrier concentration ͑or band filling͒ contrary to cerium substitution. We show that it has, however, a severe impact on hole-type carrier mobility. This feature is evidenced by focusing on the overdoped regime ͑x Ն 0.16͒ for which reduction increases the contributions of hole-type quasiparticle excitations to the Hall coefficient without affecting much the contribution from electrons. Since reduction has been also shown recently to provoke a strong suppression of antiferromagnetic order for doping close to optimal, we interpret the strong increase in mobility to result from a decreasing scattering rate related to a decreasing strength of antiferromagnetic correlations. We suggest that delocalization of hole-type carriers with reduction is achieved through the frustration of the antiferromagnetic order of as-grown nonsuperconducting composition by in-plane oxygen vacancies. We propose a comparison of ARPES data for as-grown and reduced Pr 2−x Ce x CuO 4 on the overdoped side as a possible experiment to clarify the origin of the hole-type quasiparticles with reduction.

Transport anomalies and quantum criticality in electron-doped cuprate superconductors

“…Similar behavior of the Hall coefficient was also observed in series of oxygen tuned Pr 2-x Ce x CuO 4±δ with x = 0.17 [112]. Interestingly, Ce substitution gave a quite similar Hall behavior as seen in Pr 2-x Ce x CuO 4 and La 2-x Ce x CuO 4 [113,114] (Fig.…”

Emerging superconductivity hidden beneath charge-transfer insulators

“…In (a) the Hall coefficient R H (black line) and the resistivity at μ 0 H = 14 T are plotted as a function of T for standard annealed Pr 2-x Ce x CuO 4 with x = 0.15 at μ 0 H = 14 T and in (b) R H is plotted as a function of T and x (data taken from135455). Additionally, T N and T c are plotted as a function of x ( T N taken from37 and T c from13).…”

Oxygen doping of HTSC and resistive switching in HTSC-based heterostructures

“…This fact can be understood considering weak influence of oxygen as a doping element on the properties of NCCO which has been already confirmed in some works (Higgins et al 2006;Gauthier et al 2007). Nonstoichiometric oxygen does not affect the number of carriers in NCCO and leads to disorder only.…”